I agree that GitLab is using too much RAM. Stan Hu, all time MVP record holder, will start working to reduce this. Options are removing Ruby code in Gitaly 1.1 and using multi threading in the application server.
For every release GitLab gives an MVP award to the community member who contributes in an impactful way to that release. Stan has earned it the most times: https://about.gitlab.com/mvp/
